Method and apparatus for grinding internal surfaces



March 13, 1928. 1,662,241

- A. M. DRAKE METHOD AND APPARATUS FOR GRINDING INTERNAL SURFACES Filed May 8. 1926 2 Sheets-Sheet 1 March 13, 1928. 1,662,241

A. M. DRAKE METHOD AND APPARATUS FOR GRINDING INTERNAL SURFACES Filed May 8, 1926 2 Sheets-Sheet 2 I720??? for Y Jgczen 115277 cake m be easily and conveniently 25 without any ti) larly Patented Mar. 13, 1928.

UNITED STATES PATENT OFFICE.

ALDEN M. DRAKE, OF GREENFIELD, MASSACHUSETTS, ASSIGNOR TO GREENFIELD TAP AND DIE COBPOBATION,'OF GREENFIELD, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

METHOD AND APPARATUS FOR GRINDING INTERNAL SURFACES.

Application filed Kay 8, 1926. Serial No. 107,749.

This invention relates to a method and apparatus for grinding internal surfaces in rings, sleeves,icollars, or other machine elements or metal articles. i

It is an important objeet'of my invention to provide a method of carrying out such grinding operations and an apparatus by which said method may be performed which method and'apparatus permit the work to removed and replaced and also permit the grinding wheel to be quickly and accurately trued up before a finishing cut is taken. Both of these necessary operations ma be thus performed 15 with much less expendlture of time and labor than has been heretofore required under the resent and usual practice.

A further object of my invention 1s to provide a constructlon of internal grinding ma chine in which the wheel truing device may be accurately adjusted in a fixed position closely adjacent the work, while at the same time the removal and replacement of the work may be uickly and easily performed, struction or interference by the wheel truingdevice.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particupointed out in the appended claims.

A preferred form of my improved apparatus and one by which my improved method may be conveniently carried outfs shown in the drawings in which Fig. 1 is a partial front elevation of my improved grinding apparatus, with the work and ortions of the wheel guard and casing s own in section;

Fig. 2 is a sectional plan view of the work- 4 supporting member, taken along the line 2--2 in F1g. 1; and v Fig. 3 is a left hand end elevation of the work-supporting head, looking in the direction of the arrow 3 in Fig 1.

Referring'to. the drawings, I have shown a portionv of a base or frame on which a work table 11 is slidably mounted. A bearing support 12 (Fig. 3) is secured to the table '11 mounted in one or more bearings 14, pre erably of the anti-friction type, and the bearings 14 are carried by the bearing support 12.

Y provided and is movable axially therewith. 50 A work-supporting member 13 is rotatabl The work W is held-on the work-supportmg member 13 in any convenient manner, as by clamping jaws 15 or by any other suitable clutch or clamping device.

A grinding wheel G is mounted at the forward end of a grinding shaft or spindle 16 rotated in a bearin 17 on the wheel head 18 andprojecting within the member 13. The Wheel head 18 is preferably mounted on a. cross slide 19 slidable in transverse guideways on the frame 10, said guide-ways formmg an arch over the table 11, which is slidable beneath the wheel head in longitudinal guide-ways on the frame 10.

A wheel truing device 20 (Fig. 2) is mounted on an arm 21 extending within the work-supporting member 13 at one side of the shaft 16. The truing device 20 has a base portion 22 slidable in radial guide-ways at the left hand end of the work-supporting member 13. .r

A rack bar 23 is mounted on the base portion 22 and is engaged by a pinion 24 at the lower end of a short vertical adjusting shaft 25 having a hand wheel or thumb nut 26v at its u per end. A binding screw 27 is or firmly securing the cross slide of the member 22 in any desired adjusted position. Suitable table operating mechanism M (Fig. 1) may be provided for reciprocating the table, the operation thereof being automaticall controlled by table dogs and being manna ly controlled by a handle30.

The'parts thus far described are in general substantially similar to those shown in my prior application, Serial No. 91,208, filed Feb. 27 1926, and reference-thereto may be had for. a more complete and detailed description of the mechanism.

A novel and important feature of my present invention consists in mounting the diamond point or truing device 20 within the work-supporting member 13, as in my pie I A and arrangement of the parts, very important advantages in the method of operation of the machine are rendered available.

I will now describe my preferred process or method of internal grinding, as practiced by use of the improved machine above described.

As previously stated, the truing device 20 is spaced from the rear of the work \V by a distance greater than the width of the grinding wheel G. In starting up the machine, the work table is moved so that the grinding wheel is withdrawn to clear the left hand or rear face of the work W. A new piece of work may then be secured in operative position on the member 13 by the clamping jaws 15, or in any other convenient manner.

The grinding operation is then started and the work \V is relatively rcciprocated back and forth across the face of the wheel G until the roughing out has been completed and the hole is approaching the desired finished diameter.

During this operation, the work IV does not move outward or to the right sufiiciently to engage the truing device 20 with the wheel G. Just before taking the finishing cut, however, the work table 11 is given a sufficiently increased travel to carry the truing device past the face of the grinding wheel, the effect being that of relatively withdrawing the wheel further from the work by something more than its own width.

The truing device is caused to pass by the grinding wheel and return, repeating the operation if desired, and the wheel is then ready to resume grinding operations with the face accurately trued and at a definite known distance inside of the desired finished diameter. The wheel head 18 may then be moved on its cross slide transversely of the wheel axis a distance equal to the desired increase in radius over the truing position and the work is then ground quickly and accurately to finished size.

When the grinding is finished, the work table is so positioned that the grinding wheel is housed within the work-supporting member 13 but is not engaged by the truing device 20. The work may then be freely and easily removed and replaced without obstruction by the grinding wheel or by the truing device, interference which is unavoidable when the grinding wheel enters the work from the outer side, or when the truing device is mounted at the outer side of the work.

By my inproved machine construction and by the use of my improved process, I greatly reduce the necessary relative separation of the grinding wheel and work, both for the truing operation and also for the removal and replacement of the work.

While I have shown a construction in which the grinding wheel is held in fixed position axially, while the work moves relatively thereto, it will be understood that these movements may be reversed if desired, such reversal being common and my invention not being limited specifically to a definite movement of either the wheel or the work.

In the claims the word rear is intended to indicate that face or portion of the work which is nearer the wheel head of the machine.

Ilaring thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed otherwise than as set forth in the claims, but what I claim is 1. In an internal grinding machine, a frame, an annular work-supporting member, a bearing support therefor, means to secure the work to said member, a grinding wheel, a wheel head positioned at the rear of said work-supporting member, a wheel shaft mounted in said head and projecting therefrom into said work-supporting member to present said wheel at the rear face of said work, a truing device for the wheel at the rear of the work, and means to cause relative axial travel between the wheel and work, said truing device being positioned between the work and the wheel head and being continuously spaced rearwardly from the rear face of the work a distance greater than the axial width of the grinding wheel face.

' 2. In an internal grinding machine, a frame, an annular work-supporting member, a bearing support therefor, means to secure the work to said member, a grinding wheel, a wheel head positioned at the rear of said work-supporting member, a wheel shaft mounted in said head and projecting therefrom into said work-supporting member to present said wheel at the rear face of said work, a truing device for the wheel at the rear of the work, means to cause relative axial travel between the wheel and work, and means to adjust said truing device, said truing device being positioned between the work and the wheel head and being continuously spaced rearwardly from the rear face of the work a distance greater than the axial width of the grinding wheel face.

3. In an internal grinding machine, an annular work supporting member, said member having a work-engaging ortion effective to secure the work in predetermined axial position at one end of said member, a grinding wheel arranged to project into said member, a truing device for the wheel at the rear of the work and projecting into said member, said annular member being of a size sufiiciently large to freely receive said grinding wheel and said truing device, and means to cause relative axial travel between the wheel and the work supporting member,

said truing device being positioned rearsmaller than wardly of the work-engaging portion of said member and being continuously spaced rearwardly from the rear face of the work a. distance greater than the axial width of the grinding wheel face.

4. In an internal grinding machine, a work sup orting member having an axial opening tierethrough, said member having aws or other work supporting devices adapted to receive a piece of annular work internal diameter relatively the diameter of said opening, a grinding wheel, a wheel shaft mounted to project into said member to present said wheel at the rear face of said work, a truing device for the wheel arranged in said member at the rear of said work, means to cause relative axial travel between the wheel and the work, and means to adjust said truing device, said truing device being continuously spaced rearwardly from the rear face ofthe work a distance greater than the axial width of the grinding wheel face, said axial opening through said member being of a size sufiiciently large to freely receive said grinding wheel and truing device.

5. The method of grinding internal work in a machine having a supporting member on which the work is mounted, a grinding wheel projecting into said member, a truing device mounted in said member rearwardly of the work and continuously spaced therefrom a distance greater than the axial width of said grinding wheel face, which comprises causing relative reciprocation of the grinding wheel and work to grind the work, positioning the wheel within said supporting member to permit replacement of the work, placing said truing device in a definite position relative to said supp'ortingmember and rearward of said re lacement position of the wheel and relative y se arating said wheel and work an addition rearward distance having an to true the wheel while the work is held in grinding position.

6. The method of grinding internal work in a machine having a supporting member on which the work is mounted, a grinding wheel projecting into said member, a truing device mounted in said member rearwardly of the work and continuously spaced therefrom a distance greater than the axial width of said grinding wheel face, which comprises separately supporting and rotating the wheel and thework, relatively reciprocating the wheel and work to grind the work, removing the from the front of the supporting member after relatively moving the grinding wheel rearwardly from the work and inwardly of the member to permit such work removal, and relatively moving said grinding wheel further in the same rearward direction to engage a truing device for truing the wheel betvirceen the roughing and finishing of the wor finished work outward 7. The method of grinding internal work in a machine having a supporting member on which the work is mounted, a grinding wheel projecting into said member, a truing device mounted in said member reawardly of the work and continuously spacedv therefrom a distance greater than the axial width of said grinding wheel face, which comprises separately supporting and rotating.

the wheel and the work, relatively reciproeating the wheel and work to grind the work, relatively separating the wheel from the work in a rearward direction to true the wheel after a roughing cut, finish grindin' the work, and removing the finished wor axially outward from the front of the supporting member to chanfge the work.

In testimony whereo I have hereunto aflixed my signature.

ALDEN M. DRAKE. 

